Gas mixer

Abstract

To provide a gas mixer that can reduce occurrence of resistance and mix two kinds of fluid with each other appropriately.SOLUTION: A gas mixer 100 comprises: a supply pipe 110 connected to a side surface of main piping 200; the main piping 200 which comprises a cylindrical main body part 121 having a diameter smaller than a diameter of the main piping 200 and a plurality of toric wall parts 123 and 124 protruding from an outer surface of the main body part 121 to contact an inner surface of the main piping 200, where the plurality of wall parts 123 and 124 respectively comprises notches 125 and 126 at positions different from each other; a dispersion part 120 fitted to inside of the main piping 200 so that at least a portion thereof overlaps with a connection part at which the main piping is connected to the supply pipe 110; a supply ring 130, arranged at a downstream side of the dispersion part 120, which is a cylindrical member having a diameter smaller than a diameter of the main piping 200 comprising a plurality of through-holes 131 formed to extend in a radial direction; and a sealing ring 140 arranged at a downstream side of the supply ring 130 and fitted to inside of the main piping 200.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas mixer.

Background Art

[0002] Patent Document 1 describes a stationary gas mixer for mixing components of exhaust gas of an internal combustion engine with a reducing agent. Specifically, the stationary gas mixer described in Patent Document 1 includes at least two baffle plates disposed one behind the other in the direction of the flow of the components of the mixture inside a housing. Further, the holes of the preceding baffle plate are located in one half on one side of the baffle plate, while the holes of the subsequent baffle plate are located in the other half on the other side of the baffle plate. Thereby, a turbulent flow is generated in the mixture flowing inside the housing, and it is intended that the mixture is preferably mixed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in Patent Document 1, there is a problem that a large resistance is generated because the mixture collides with the baffle plate.

[0005] The present invention has been made to solve such problems, and an object thereof is to provide a gas mixer that can reduce the generation of resistance and preferably mix two fluids.

Means for Solving the Problems

[0006] The gas mixer according to the first aspect of the present invention is a gas mixer that mixes a main fluid flowing through a main pipe and a fluid to be mixed in the main pipe, and includes a supply pipe connected to a side surface of the main pipe, a cylindrical main body portion having a diameter smaller than that of the main pipe, and a plurality of annular wall portions protruding from an outer surface of the main body portion and abutting against an inner surface of the main pipe. The plurality of wall portions are provided with notches at different positions. A dispersion portion is fitted inside the main pipe so that at least a part of a connection portion where the main pipe and the supply pipe are connected overlaps. A supply ring is disposed downstream of the dispersion portion inside the main pipe and is a cylindrical member having a diameter smaller than that of the main pipe, and includes a plurality of through holes provided to extend in the radial direction. A sealing ring is disposed downstream of the supply ring and is fitted inside the main pipe.

Advantages of the Invention

[0007] According to the gas mixer according to the first aspect of the present invention, the fluid to be mixed supplied from the supply pipe is dispersed in the space between the dispersion portion and the main pipe, and the dispersed fluid to be mixed is supplied from the plurality of through holes of the supply ring into the supply ring and mixed with the main fluid. The fluid to be mixed flows into the main fluid from a plurality of directions along a direction intersecting the direction in which the main fluid flows through the plurality of through holes of the supply ring. Therefore, the main fluid and the fluid to be mixed can be preferably mixed without arranging a baffle plate inside the main pipe. Thus, it is possible to provide a gas mixer that reduces the generation of resistance and can preferably mix two fluids.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following Embodiment 1. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

[0010] (First Embodiment) Hereinafter, with reference to FIG. 1, the gas mixer 100 according to the first embodiment will be described. FIG. 1 is a partial cross-sectional view showing the gas mixer 100. Specifically, in FIG. 1, the main pipe 200 and the supply pipe 110 are shown in cross-section, and the other parts of the gas mixer 100 are shown in side view. Also, in FIG. 1, the flow of the main fluid flowing through the main pipe 200 is indicated by a hatched arrow, and the flow of the fluid to be mixed is indicated by a white arrow. Note that the right-handed XYZ orthogonal coordinates shown in FIG. 1 and other drawings are for convenience in explaining the positional relationship of the components. The +Z direction is vertically upward, the XY plane is the horizontal plane, the +X direction is the axial direction of the main pipe 200 and is the direction from upstream to downstream, and is common among the drawings. FIG. 2 is a perspective view showing the gas mixer 100. In FIG. 2, the main pipe 200 and the supply pipe 110 are shown by broken lines, and the other parts of the gas mixer 100 are shown by solid lines. Also, in FIG. 2, the flow of the fluid to be mixed is indicated by a black arrow. FIG. 3 is a cross-sectional view taken along the cutting line III-III of FIG. 2.

[0011] As shown in FIGS. 1 to 3, the gas mixer 100 includes a supply pipe 110, a dispersion part 120, a supply ring 130, and a sealing ring 140. The supply pipe 110, the dispersion part 120, the supply ring 130, and the sealing ring 140 are formed using, for example, stainless steel (SUS; Stainless Used Steel). Note that the material of the supply pipe 110, the dispersion part 120, the supply ring 130, and the sealing ring 140 may be changed according to the chemical properties of the main fluid and the fluid to be mixed that the gas mixer 100 mixes.

[0012] The supply pipe 110 is connected to the side surface of the main pipe 200. Specifically, the supply pipe 110 is connected to the side surface of the main pipe 200 such that the axial direction (X-axis direction) of the main pipe 200 and the axial direction of the supply pipe 110 intersect. Note that the main pipe 200 is a pipe through which the main fluid flows. Also, the supply pipe 110 is a pipe that supplies a fluid to be mixed with a smaller flow rate than the flow rate of the main fluid. For example, the main fluid is a fluid containing components of the exhaust gas of an internal combustion engine, and the fluid to be mixed is a fluid containing a reducing agent.

[0013] As shown in FIGS. 1 and 2, the dispersion part 120 is fitted inside the main pipe 200 such that at least a part thereof overlaps with the connection part where the main pipe 200 and the supply pipe 110 are connected in the X-axis direction. The dispersion part 120 includes a main body part 121, a first wall part 122, a second wall part 123, and a third wall part 124.

[0014] The main body part 121 is a cylindrical member having a diameter smaller than the diameter of the main pipe 200. The inside of the cylinder of the main body part 121 communicates with the inside of the main pipe 200, and the main fluid flowing through the main pipe 200 flows into the inside of the main body part 121.

[0015] The first wall part 122 is an annular wall that protrudes radially from the upstream end of the outer surface of the main body part 121 and abuts against the inner surface of the main pipe 200. Also, the first wall part 122 is located upstream of the connection part where the main pipe 200 and the supply pipe 110 are connected. The first wall part 122 can prevent the main fluid from flowing into the space between the connection part where the main pipe 200 and the supply pipe 110 are connected and the outer surface of the main body part 121. Also, the main fluid blocked by the first wall part 122 flows into the inside of the main body part 121. Note that the inner surface of the main body part 121 corresponding to the first wall part 122 may be inclined such that the diameter gradually decreases from upstream to downstream (in the +X-axis direction) as shown by the dashed line in FIG. 1. Thereby, the resistance generated by the main fluid being blocked by the first wall part 122 can be reduced.

[0016] The second wall portion 123 is a substantially annular wall that protrudes radially from the downstream side of the first wall portion 122 on the outer surface of the main body portion 121 and abuts against the inner surface of the main pipe. Further, the second wall portion 123 is located on the downstream side of the connection portion where the main pipe 200 and the supply pipe 110 are connected. Further, the second wall portion 123 includes a plurality of notches 125 formed by cutting the second wall portion 123 in the X-axis direction. In the example shown in FIGS. 1 and 2, two notches 125 are formed at positions 90° circumferentially away from the connection portion between the main pipe 200 and the supply pipe 110. Note that the number, width, and position of the notches 125 may be changed depending on the viscosity, density, flow rate, etc. of the fluid to be mixed.

[0017] The third wall portion 124 is an annular wall that protrudes radially from the downstream end of the main body portion 121 and abuts against the inner surface of the main pipe 200. Further, the third wall portion 124 includes a plurality of notches 126 formed by cutting the third wall portion 124 in the X-axis direction. In the example shown in FIGS. 1 to 3, six notches 126 are formed at intervals of 60° circumferentially with the position of the connection portion between the main pipe 200 and the supply pipe 110 being 0°. Note that the number, width, and position of the notches 126 may be changed depending on the viscosity, density, flow rate, etc. of the fluid to be mixed.

[0018] And the circumferential position where the notch 125 is provided in the second wall portion 123 is different from the circumferential position where the notch 126 is provided in the third wall portion 124. Thereby, the fluid to be mixed that has flowed into the space between the inner surface of the main pipe 200 and the outer surface of the main body portion 121 from the supply pipe 110 flows along the outer surface of the main body portion 121, passes through the notch 125, then further flows along the outer surface of the main body portion 121, passes through the notch 126, and moves to the downstream side of the dispersion portion 120. Therefore, the fluid to be mixed supplied from the supply pipe 110 is dispersed throughout along the inner surface of the main pipe 200 inside the main pipe 200.

[0019] In the examples shown in FIGS. 1 and 2, an example is shown in which the dispersion part 120 includes two wall parts 123 and 124 having notches 125 and 126. However, the number of wall parts 123 and 124 included in the dispersion part 120 is not limited as long as it is 2 or more. The number of wall parts 123 and 124 included in the dispersion part 120 may be changed according to the viscosity, density, and flow rate of the fluid to be mixed.

[0020] The supply ring 130 is disposed inside the main pipe 200 and on the downstream side of the dispersion part 120. The supply ring 130 is a cylindrical member having a diameter smaller than that of the main pipe 200. The inside of the supply ring 130 communicates with the inside of the cylinder of the dispersion part 120, and the main fluid flowing through the inside of the dispersion part 120 flows into the inside of the supply ring 130. In the examples shown in FIGS. 1 to 3, the supply ring 130 is a cylindrical member having an octagonal outer shape and a circular inner shape in a cross section parallel to the Y-Z plane (see FIG. 3). The supply ring 130 includes a plurality of through holes 131 extending in the radial direction. In the examples shown in FIGS. 1 to 3, a total of 8 through holes 131 are provided, one from each side of the octagon toward the inside in the radial direction. Thereby, the fluid to be mixed that has flowed into the space between the inner surface of the main pipe 200 and the outer surface of the supply ring 130 through the notch 126 of the third wall part 124 flows into the inside of the supply ring 130 through the through hole 131 and is mixed with the main fluid. The fluid to be mixed flows into the main fluid from a plurality of directions along a direction intersecting the direction in which the main fluid flows through the plurality of through holes 131 of the supply ring 130. Therefore, the main fluid and the fluid to be mixed can be suitably mixed without arranging a baffle plate inside the main pipe 200. Thereby, the distance of the flow path of the main pipe 200 required for mixing the main fluid and the fluid to be mixed can be shortened, and the main pipe 200 can be made compact. Note that the number and diameter size of the through holes 131 may be changed according to the ratio of the flow rate of the main fluid to the flow rate of the fluid to be mixed. Further, the outer shape of the supply ring 130 is not limited to an octagon.

[0021] Further, in the examples shown in FIGS. 1 to 3, the through hole 131 is provided at a position shifted (separated) in the circumferential direction from a radial axis (indicated by a one-dot chain line in FIG. 3) that intersects the axis of the main pipe 200 (an axis parallel to the X axis). As a result, an eddy current is formed in the direction indicated by the solid arrow in FIG. 3 by the fluid to be mixed that has flowed into the inside of the supply ring 130 through the through hole 131. Therefore, due to the eddy current, the interface between the main fluid and the fluid to be mixed is easily disturbed, and furthermore, the distance of the flow path of the main pipe 200 required to mix the main fluid and the fluid to be mixed can be shortened.

[0022] The sealing ring 140 is disposed inside the main pipe 200 on the downstream side of the supply ring 130 and is fitted inside the main pipe 200. The sealing ring 140 seals the space between the inner surface of the main pipe 200 and the outer surface of the supply ring 130. Thereby, the sealing ring 140 prevents the fluid to be mixed from being mixed into the main fluid without passing through the through hole 131. Further, the inside of the sealing ring 140 communicates with the inside of the supply ring 130, and the main fluid in which the fluid to be mixed flowing through the inside of the supply ring 130 is mixed flows into the inside of the sealing ring 140.

[0023] Next, the assembly of the gas mixer 100 will be described. First, the dispersion part 120, the supply ring 130, and the sealing ring 140 are joined by welding or the like. Next, a through hole for communicating with the supply pipe 110 is provided in the side surface of the main pipe 200 cut to a length capable of enclosing the joined dispersion part 120, supply ring 130, and sealing ring 140, and the supply pipe 110 is joined by welding or the like at the position of the through hole. Next, the joined dispersion part 120, supply ring 130, and sealing ring 140 are fitted inside the main pipe 200 and fixed by welding or the like. Next, the main pipe 200 in which the dispersion part 120, supply ring 130, and sealing ring 140 are fitted is joined to another main pipe 200 by welding or the like. Note that the joining of the main pipe 200 in which the dispersion part 120, supply ring 130, and sealing ring 140 are fitted and another main pipe 200 may be realized by joining the flanges of the two main pipes using bolts or the like when the main pipe 200 is provided with flanges.

[0024] As described above, in the gas mixer 100 according to the first embodiment, the fluid to be mixed supplied from the supply pipe 110 is dispersed in the space between the dispersion unit 120 and the main pipe 200, and the dispersed fluid to be mixed is supplied from the plurality of through holes 131 of the supply ring 130 into the supply ring 130 and mixed with the main fluid. The fluid to be mixed flows into the main fluid from a plurality of directions along a direction intersecting the direction in which the main fluid flows through the plurality of through holes 131 of the supply ring 130. Therefore, even without arranging a baffle plate inside the main pipe 200, the main fluid and the fluid to be mixed can be suitably mixed. Thus, it is possible to provide the gas mixer 100 that reduces the generation of resistance and can suitably mix two fluids.

[0025] Specifically, the greater the difference between the flow rate of the main fluid and the flow rate of the fluid to be mixed, simply supplying the fluid to be mixed from the supply pipe 110 connected to the main pipe 200 into the main pipe 200 will not cause turbulence at the interface between the main fluid and the fluid to be mixed, and the main fluid and the fluid to be mixed will not naturally and uniformly mix. Also, if a baffle plate is arranged inside the main pipe 200, resistance will be generated due to the fluid colliding with the baffle plate. Further, a method of creating a vortex flow in the fluid flowing inside the main pipe 200 by providing blades inside the main pipe 200 can also be considered. However, in this case, since both the main fluid and the fluid to be mixed form a vortex flow, a vortex flow will be formed while the interface between the main fluid and the fluid to be mixed is maintained. Therefore, a long flow path is required until the main fluid and the fluid to be mixed are completely stirred. Furthermore, complicated processing techniques are required for manufacturing the blades, and special welding techniques are required to attach the blades inside the main pipe 200.

[0026] On the other hand, in the gas mixer 100 according to the first embodiment, the fluid to be mixed dispersed in the space between the dispersion unit 120 and the main pipe 200 flows into the main fluid from a plurality of directions along a direction intersecting the direction in which the main fluid flows through the plurality of through holes 131 of the supply ring 130. Therefore, the main fluid and the fluid to be mixed can be preferably mixed without arranging a baffle plate or blades inside the main pipe 200. Further, the dispersion unit 120, the supply ring 130, and the sealing ring 140 can be manufactured by machining using a lathe, and the gas mixer 100 can be installed on the main pipe 200 by the simple assembly process as described above. Therefore, the gas mixer 100 can be installed on the main pipe 200 without requiring special processing technology or special welding technology.

[0027] Further, the through holes 131 are provided at positions shifted (separated) in the circumferential direction from a radial axis (indicated by a one-dot chain line in FIG. 3) intersecting the axis of the main pipe 200 (an axis parallel to the X axis). Thereby, the interface between the main fluid and the fluid to be mixed is easily disturbed by the vortex formed by the fluid to be mixed flowing into the inside of the supply ring 130 through the through holes 131, and further, the distance of the flow path of the main pipe 200 required for mixing the main fluid and the fluid to be mixed can be shortened. Actually, when mixing the fluid to be mixed with a flow rate of 24 liters / minute into the main fluid with a flow rate of 1700 liters / minute using the gas mixer 100, as a result of analyzing the distribution of the fluid to be mixed at a position 150 mm downstream from the supply pipe 110 by CAE analysis, it was confirmed that the fluid to be mixed was uniformly distributed with respect to the main fluid.

[0028] Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist. For example, in a hydrogen engine, the gas mixer 100 can also be diverted when mixing air with hydrogen gas.

Explanation of Reference Numerals

[0029] 100 Gas mixer 110 Supply pipe 120 Dispersion unit 121 Main body 122 First wall portion 123 Second wall portion 124 Third wall portion 125, 126 Notch 130 Supply ring 131 Through hole 140 Sealing ring

Claims

**Claim 1** A gas mixer that mixes a main fluid flowing through a main pipe and a fluid to be mixed in the main pipe, a supply pipe connected to a side surface of the main pipe, a cylindrical main body portion having a diameter smaller than that of the main pipe, and a plurality of annular wall portions protruding from an outer surface of the main body portion and contacting an inner surface of the main pipe, wherein the plurality of wall portions are provided with notches at different positions, a dispersion portion fitted inside the main pipe so that at least a part of a connection portion where the main pipe and the supply pipe are connected overlaps, a supply ring disposed inside the main pipe on the downstream side of the dispersion portion, the supply ring being a cylindrical member having a diameter smaller than that of the main pipe and including a plurality of through holes extending in the radial direction, a sealing ring disposed on the downstream side of the supply ring and fitted inside the main pipe, characterized by comprising a gas mixer.

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